diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
new file mode 100644
index 000000000000..9e1a29e079e6
--- /dev/null
+++ b/.github/workflows/docs.yml
@@ -0,0 +1,50 @@
+on:
+  pull_request:
+    branches:
+      - main
+name: docs
+
+permissions:
+  contents: read
+
+jobs:
+  docs:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v3
+    - name: Setup Python
+      uses: actions/setup-python@v4
+      with:
+        python-version: "3.9"
+    - name: Install nox
+      run: |
+        python -m pip install --upgrade setuptools pip wheel
+        python -m pip install nox
+    - name: Run docs
+      env:
+        BUILD_TYPE: presubmit
+        TEST_TYPE: docs
+        PY_VERSION: "3.9"
+      run: |
+        ci/run_conditional_tests.sh
+  docfx:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v3
+    - name: Setup Python
+      uses: actions/setup-python@v4
+      with:
+        python-version: "3.9"
+    - name: Install nox
+      run: |
+        python -m pip install --upgrade setuptools pip wheel
+        python -m pip install nox
+    - name: Run docfx
+      env:
+        BUILD_TYPE: presubmit
+        TEST_TYPE: docfx
+        PY_VERSION: "3.9"
+      run: |
+        ci/run_conditional_tests.sh
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
new file mode 100644
index 000000000000..40b70a4842e5
--- /dev/null
+++ b/.github/workflows/lint.yml
@@ -0,0 +1,37 @@
+on:
+  pull_request:
+    branches:
+      - main
+name: lint
+
+permissions:
+  contents: read
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v3
+    - name: Setup Python
+      uses: actions/setup-python@v4
+      with:
+        python-version: "3.9"
+    - name: Install nox
+      run: |
+        python -m pip install --upgrade setuptools pip wheel
+        python -m pip install nox
+    - name: Run lint
+      env:
+        BUILD_TYPE: presubmit
+        TEST_TYPE: lint
+        PY_VERSION: "3.9"
+      run: |
+        ci/run_conditional_tests.sh
+    - name: Run lint_setup_py
+      env:
+        BUILD_TYPE: presubmit
+        TEST_TYPE: lint_setup_py
+        PY_VERSION: "3.9"
+      run: |
+        ci/run_conditional_tests.sh
diff --git a/.github/workflows/unittest.yml b/.github/workflows/unittest.yml
new file mode 100644
index 000000000000..368bc440a6c1
--- /dev/null
+++ b/.github/workflows/unittest.yml
@@ -0,0 +1,93 @@
+on:
+  pull_request:
+    branches:
+      - main
+name: unittest
+
+permissions:
+  contents: read
+
+jobs:
+  unit:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python: ['3.7', '3.8', '3.9', '3.10']
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v3
+    - name: Setup Python
+      uses: actions/setup-python@v4
+      with:
+        python-version: ${{ matrix.python }}
+    - name: Install nox
+      run: |
+        python -m pip install --upgrade setuptools pip wheel
+        python -m pip install nox
+    - name: Run unit tests
+      env:
+        COVERAGE_FILE: .coverage-${{ matrix.python }}
+        BUILD_TYPE: presubmit
+        TEST_TYPE: unit
+        PY_VERSION: ${{ matrix.python }}
+      run: |
+        ci/run_conditional_tests.sh
+    - name: Upload coverage results
+      uses: actions/upload-artifact@v3
+      with:
+        name: coverage-artifacts
+        path: .coverage-${{ matrix.python }}
+  prerelease:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python: ['3.10']
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v3
+    - name: Setup Python
+      uses: actions/setup-python@v4
+      with:
+        python-version: ${{ matrix.python }}
+    - name: Install nox
+      run: |
+        python -m pip install --upgrade setuptools pip wheel
+        python -m pip install nox
+    - name: Run prerelease tests
+      env:
+        BUILD_TYPE: presubmit
+        TEST_TYPE: prerelease
+        PY_VERSION: ${{ matrix.python }}
+      run: |
+        ci/run_conditional_tests.sh
+
+  cover:
+    runs-on: ubuntu-latest
+    needs:
+        - unit
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v3
+    - name: Setup Python
+      uses: actions/setup-python@v4
+      with:
+        python-version: "3.10"
+    - name: Set number of files changes in packages directory
+      id: packages
+      run: echo "::set-output name=num_files_changed::$(git diff HEAD~1 -- packages/*.yml | wc -l)"
+    - name: Install coverage
+      if: ${{ steps.date.packages.num_files_changed > 0 }}
+      run: |
+        python -m pip install --upgrade setuptools pip wheel
+        python -m pip install coverage
+    - name: Download coverage results
+      if: ${{ steps.date.packages.num_files_changed > 0 }}
+      uses: actions/download-artifact@v3
+      with:
+        name: coverage-artifacts
+        path: .coverage-results/
+    - name: Report coverage results
+      if: ${{ steps.date.packages.num_files_changed > 0 }}
+      run: |
+        coverage combine .coverage-results/.coverage*
+        coverage report --show-missing --fail-under=100
diff --git a/ci/run_conditional_tests.sh b/ci/run_conditional_tests.sh
new file mode 100755
index 000000000000..b1247466e47d
--- /dev/null
+++ b/ci/run_conditional_tests.sh
@@ -0,0 +1,118 @@
+#!/bin/bash
+# Copyright 2022 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This script requires the following environment variables to be set:
+# `BUILD_TYPE` should be one of ["presubmit", "continuous"]
+# `TEST_TYPE` should be one of ["lint", "lint_setup_py", "docs", "docfx", "prerelease"]
+# `PY_VERSION` should be one of ["3.7", "3.8", "3.9", "3.10", "3.11"]
+
+# `TEST_TYPE` and `PY_VERSION` are required by the script `ci/run_single_test.sh`
+
+# This script will determine which directories have changed
+# under the `packages` folder. For `BUILD_TYPE=="presubmit"`,
+# we'll compare against the `packages` folder in HEAD,
+# whereas for `BUILD_TYPE=="continuous"` we'll compare changes
+# with HEAD~1. For all directories that have changed files, we will
+# run the script located at `${PROJECT_ROOT}/ci/run_single_test.sh`.
+
+# `-e` enables the script to automatically fail when a command fails
+# `-o pipefail` sets the exit code to non-zero if any command fails,
+# or zero if all commands in the pipeline exit successfully.
+set -eo pipefail
+
+export PROJECT_ROOT=$(realpath $(dirname "${BASH_SOURCE[0]}")/..)
+
+# A script file for running the test in a sub project.
+test_script="${PROJECT_ROOT}/ci/run_single_test.sh"
+
+if [ ${BUILD_TYPE} == "presubmit" ]; then
+    # For presubmit build, we want to know the difference from the
+    # common commit in origin/main.
+    GIT_DIFF_ARG="origin/main..."
+
+    # Then fetch enough history for finding the common commit.
+    git fetch origin main --deepen=200
+
+elif [ ${BUILD_TYPE} == "continuous" ]; then
+    # For continuous build, we want to know the difference in the last
+    # commit. This assumes we use squash commit when merging PRs.
+    GIT_DIFF_ARG="HEAD~.."
+
+    # Then fetch one last commit for getting the diff.
+    git fetch origin main --deepen=1
+
+else
+    # Run everything.
+    GIT_DIFF_ARG=""
+fi
+
+# Then detect changes in the test scripts.
+
+set +e
+git diff --quiet ${GIT_DIFF_ARG} ci
+changed=$?
+set -e
+if [[ "${changed}" -eq 0 ]]; then
+    echo "no change detected in ci"
+else
+    echo "change detected in ci, we should test everything"
+    GIT_DIFF_ARG=""
+fi
+
+# Now we have a fixed list, but we can change it to autodetect if
+# necessary.
+
+subdirs=(
+    packages
+)
+
+RETVAL=0
+
+for subdir in ${subdirs[@]}; do
+    for d in `ls -d ${subdir}/*/`; do
+        should_test=false
+        if [ -n "${GIT_DIFF_ARG}" ]; then
+            echo "checking changes with 'git diff --quiet ${GIT_DIFF_ARG} ${d}'"
+            set +e
+            git diff --quiet ${GIT_DIFF_ARG} ${d}
+            changed=$?
+            set -e
+            if [[ "${changed}" -eq 0 ]]; then
+                echo "no change detected in ${d}, skipping"
+            else
+                echo "change detected in ${d}"
+                should_test=true
+            fi
+        else
+            # If GIT_DIFF_ARG is empty, run all the tests.
+            should_test=true
+        fi
+        if [ "${should_test}" = true ]; then
+            echo "running test in ${d}"
+            pushd ${d}
+            # Temporarily allow failure.
+            set +e
+            ${test_script}
+            ret=$?
+            set -e
+            if [ ${ret} -ne 0 ]; then
+                RETVAL=${ret}
+            fi
+            popd
+        fi
+    done
+done
+
+exit ${RETVAL}
diff --git a/ci/run_single_test.sh b/ci/run_single_test.sh
new file mode 100755
index 000000000000..4564233a6899
--- /dev/null
+++ b/ci/run_single_test.sh
@@ -0,0 +1,90 @@
+#!/bin/bash
+#
+# Copyright 2022 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This script requires the following environment variables to be set:
+# `TEST_TYPE` should be one of ["lint", "lint_setup_py", "docs", "docfx", "prerelease"]
+# `PY_VERSION` should be one of ["3.7", "3.8", "3.9", "3.10", "3.11"]
+
+# This script is called by the `ci/run_conditional_tests.sh` script.
+# A specific `nox` session will be run, depending on the value of 
+# `TEST_TYPE` and `PY_VERSION`. For example, if `TEST_TYPE` is
+# `lint`, the `nox -s lint` session will be run.
+
+
+set -e
+
+if [ -z "${TEST_TYPE}" ]; then
+    echo "missing TEST_TYPE env var"
+    exit 1
+fi
+
+if [ -z "${PY_VERSION}" ]; then
+    echo "missing PY_VERSION env var"
+    exit 1
+fi
+
+# Don't fail on errors so we can capture all of the output
+set +e
+
+case ${TEST_TYPE} in
+    lint)
+        nox -s lint
+        retval=$?
+        ;;
+    lint_setup_py)
+        nox -s lint_setup_py
+        retval=$?
+        ;;
+    docs)
+        nox -s docs
+        retval=$?
+        ;;
+    docfx)
+        nox -s docfx
+        retval=$?
+        ;;
+    prerelease)
+        nox -s prerelease_deps-3.10
+        retval=$?
+        ;;
+    unit)
+        case ${PY_VERSION} in
+        "3.7")
+            nox -s unit-3.7
+            retval=$?
+            ;;
+        "3.8")
+            nox -s unit-3.8
+            retval=$?
+            ;;
+        "3.9")
+            nox -s unit-3.9
+            retval=$?
+            ;;
+        "3.10")
+            nox -s unit-3.10
+            retval=$?
+            ;;
+        "3.11")
+            nox -s unit-3.11
+            retval=$?
+            ;;
+        *)
+            ;;
+        esac
+esac
+
+exit ${retval}